Override upgrade height delay for local devnets

[rootulp]

Context

After the signal module receives a successful MsgTryUpgrade, there is an upgrade height delay of N blocks before the state machine upgrades from v2 -> v3

Problem

The upgrade height delay is too long for testing and local development purposes.

Proposal

For local devnets (i.e. one started via ./single-node.sh) consider overriding the upgrade height delay to something like 1 block.

[rootulp]

Related: #3979

[rootulp]

Looks like we can do this in two ways:

1. Via OverrideUpgradeHeightDelayStr
2. Via special casing the upgrade height for blockchains with the chain-id "test" in here

[rootulp]

It's a bit confusing that we have multiple ways to override this field. In a call right after I got back from vacation, I recall discussing this with @evan-forbes @cmwaters and pretty sure we agreed to use the chain-id to override configs so I plan on removing the ability to override the upgrade height via OverrideUpgradeHeightDelayStr